Tonight, a stunning look inside the world of real estate. You trust your broker, but what happens when you look the we're way? Tonight, a brand-new meaning to the term open house. Here's Debra Roberts. I've been in your house and your house and your house. I'm not a burglar. I'm a realtor. Reporter: Phil Dunphy of ABC's "Modern family" may be a honest guy, but in real life, it's more complicated. They've been caught all over the country. Stealing jewelry in Arizona and pilfering prescription meds in Florida. In homes they're supposed to be selling. And watch this. This Maryland realtor was caught red handed on surveillance tape rifling through a woman's drawers and pocketing undergarments. To have somebody come in and do these kind of acts or steal your things, it's a ultimate violation of trust, in my opinion. Reporter: Realtor Brendon Desimone is the author of next generation real estate. How do you pick a realtor? How do you know who you can trust? Ask for a referral from friends and family. You have to really check their character. What kind of person are they? Just cause they've done a lot of deals doesn't really mean they're trustworthy. Reporter: Rich Weiner would find out the hard way. He caught his realtor behaving badly in one of the most jaw-dropping cases ever. This is our marital bed. They just had sex on it. They're naked, walking around the room, and it's like, this is just incredible. Reporter: Do you remember your first reaction when you saw this? Yeah, I was like, "Are you kidding me?" This is -- like, insane. We hired him to sell the house, and this is what he's doing in it. Reporter: He is bob Lindsay. Here I am with bob Lindsay. How you doing bob? Very well, thanks. Reporter: A top N.J. Coldwell banker, real estate agent rich trusted him to sell their cherished home. How did you decide upon bob Lindsay as your real estate agent? He was a great guy, very personable. 35 years experience. He taught ethics. And, it's like, "Wow, we hit the jackpot." Reporter: In fact, rich and Sandee were happy to roll the dice when he says Lindsay suggested that he go big in their asking price. Between $550 and $5. Reporter: How much had you paid for it? Like, $250,000. So that would be a great profit. Yes. Reporter: In the listing for the house, Lindsay played up of the house's character and charm, the updated master bath and kitchen and wood burning fireplace. The Weiners assumed their agent was working hard to reel in a buyer. You had confidence in him. Absolutely. We trusted him with everything. Reporter: The Weiners had such faith in Lindsay that he says they went out on a limb, buying and moving into a new home while their Tudor was renovated to fetch top dollar. And for peace of mind they made sure their home was secured. You decided to equip the house with motion activated cameras. Why? We're very security conscious. So we always keep on our wired alarm system. And we were told by bob that, "Hey, you know, with realtor traffic you can't keep that system on because realtors are going to be setting off alarms throughout the neighborhood left and right." Reporter: So with the alarm turned off at their realtor's request but the motion activated cameras turned on, Sandee Weiner happened to be looking at the live feed of the camera one night and got the shock of her life. She comes racing up the stairs and she was like, "Oh my god, the house is being broken into!" So she calls 911, and the Wayne police, responded almost immediately. Reporter: The Weiners were glued to their screen as officers arrive in the darkened house. What you're going to see here is -- is one of the policemen coming into the room. There he is now. Reporter: There's the officer. He's got his flashlight and bob Lindsay is getting dressed. Reporter: The couple was thoroughly confused until they hit the rewind button and, rich says, he discovered weeks worth of x-rated videos starring their realtor bob Lindsay and this woman. Watch them covering their tracks making the bed following a daytime romp. In fact, rich says his camera caught them 13 times having sexual encounters over a period of seven weeks. After this makeout session they suddenly become aware of the camera. Here they're looking right up at the kitchen camera. Reporter: They certainly don't seem to be worried or concerned that they may be caught. Not at all. Which is the amazing part about all this. Reporter: So who was the mystery woman in bob Lindsay's embrace? She's Jeanmarie Phelan, a fellow Coldwell banker real estate agent, who later admitted a three-year affair with Lindsay. These two people clearly screwed up. Yes. Reporter: Is it worth humiliating them? Hurting their families? And basically airing dirty laundry in public? Their families were already aware of the affair. My clients gave them the keys to their house, so we're suing for a breach of trust, negligence. Reporter: Coldwell banker declined our request for an interview but offered a statement saying -- we ceased our affiliation with the agents. The conduct at the home does not in any way represent how we conduct business as a company. We hold affiliated agents to the highest ethical standards." Lindsay and jeanemarie Phelan both declined on camera interviews but Lindsay's lawyer sent us this statement. My client entered their home on occasion for purposes that were unauthorized. The balance of the Weiner's claims are either false and or exaggerated and can and will be exposed by clear and irrefutable evidence. Lindsay and Phelan are countersuing the wieners, claiming he attempted to extort a million dollars or he would give the compromising material to the media. My clients never asked for a dime from either Mr. Lindsay or Ms. Phelan. There was no extortion attempt. There was nothing like that. And remember that juicy asking price of $525,000? Well the home on maple Ave sold for $419,000 -- $100,000 less than Lindsay said he could get. He overpriced the house to keep the traffic away so he could use the house. He was going to make money selling the house, but just not today. He can use it as a cheap motel today, sell it tomorrow. Reporter: Do you think that person should still be practicing? Absolutely not. That person should lose their license immediately. They shouldn't be allowed to enter anybody's home ever. Reporter: What would you say if I told you that bob Lindsay is still selling homes with another firm? That's the most shocking part of this entire story, that he's still selling real estate.

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